Outlook mobile Access Exchange server 2003 ent edition error 404

HI,
I am running exchange server 2003 ent edition. From yesterday my mobile users are unable to access exchange server from mobile devices. My OWA works fine. From IIS the virtual directory access seems fine, also internally the webaddress for OMA is fine too i.e I can access 'http://exchange2/OMA' its fine but from web browser the 'page not found error 404' comes up' when I browse 'http://mail.mydomain.com/exchange/oma' the username and password window comes up I put in the credentials and then the page not found comes up error 404.....nothing has been changed. see attached. Help plzoma2.docx

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Please have a read through my Exchange 2003 / Activesync article and check your IIS settings, run the test on the test site (without using Autodiscover anything) and report back any issues my article doesn't cover: